Why Do Certain Lights Generate Heat?

When choosing the right lighting solution for you needs, the matter of heat might come up. While you know a light fixture produces illumination, the fact that it produces heat is often a more confusing topic in the world of lighting. So why do certain lights generate heat? Are there options with less heat and does it matter? Let's take a closer look at this topic for a better understanding.

What Causes Some Lights to Generate Heat?

The simple answer is that there is a lack of efficiency in converting energy into illumination and that energy is converted to heat loss instead of illumination. While the main goal of a light is to create light, the matter of heat dates all the way back to the earliest models of light bulbs and fixture types. Early fixtures created more heat than illumination because the designs were less efficient than what modern counterparts would eventually offer. Lighting advancements would continue to be made which would allow for a better ratio of light produced to heat loss produced with incandescent being the first to offer a better balance. While incandescent was an improvement, they still created a lot of heat loss during production. It wasn't until options like fluorescent and the improved compact fluorescents came on the scene that there was more light than heat. These options were able to produce illumination without as much heat loss because of the way they operate.

The operation of the light is the main determining factor of how much heat loss it will experience. An incandescent bulb uses an electric current to heat up a filament. While the glowing of the filament produces illumination, there is a lot of heat required to heat up the filament which is why an incandescent bulb is usually hot to the touch. An incandescent bulb is estimated to only use 10% of the energy consumed to create light while the other 90% is lost to heat during the production of that illumination. A fluorescent lamp uses a glass tube instead of a filament where the electric current flows. The tube is coated on the inside with a phosphor coating and the tube is filled with mercury gas. The electrons collide with the mercury atoms to produce an unseen ultraviolet light which is then absorbed by the phosphor to create the visible illumination. A fluorescent uses 85% of its energy to produce illumination with the rest lost to heat loss during light production. This is a step in the right direction over incandescent and other less efficient options. When looking at the options with the least heat loss and therefore best efficiency, LED is the winner. Light-emitting diodes produce light by way of a semiconductor chip with a negatively charged terminal and a positively charged terminal. The electrons collide as they move from negative to positive which creates light. LEDs use 90-95% of energy to create illumination with practically no heat loss.

Why does it all matter?

Lights creating heat loss matters for two big reasons. For starters, a light that uses more energy on heat instead of illumination is less efficient. This lack of efficiency means a higher utility bill over more efficient solutions. It also matters because high heat lamps can decrease the life of your fixture or internal elements of the fixture. If you want an option that won't run up energy costs or eventually damage your ballasts or driver on the fixture, you want an option with practically no heat loss such as LED.